<template>
  <div>
    <div class="goods">
      <div class="menu-wrapper" id="menu">
        <ul>
          <!--current  @click="clickMenuItem(index)"-->
          <li class="menu-item" v-for="(good, index) in goods" :key="index"
              :class="{current: index===currentIndex}" @click="clickMenuItem(index)">
            <span class="text bottom-border-1px">
              <img class="icon" :src="good.icon" v-if="good.icon">
              {{good.name}}
            </span>
          </li>
        </ul>
      </div>
      <div class="foods-wrapper">
        <ul ref="foodsUl">
          <li class="food-list-hook" v-for="(good, index) in goods" :key="index">
            <h1 class="title">{{good.name}}</h1>
            <ul>
              <li class="food-item bottom-border-1px" v-for="(food, index) in good.foods"
                  :key="index" @click="showFood(food)">
                <div class="icon">
                  <img width="57" height="57" :src="food.icon">
                </div>
                <div class="content">
                  <h2 class="name">{{food.name}}</h2>
                  <p class="desc">{{food.description}}</p>
                  <div class="extra">
                    <span class="count">月售{{food.sellCount}}份</span>
                    <span>好评率{{food.rating}}%</span>
                  </div>
                  <div class="price">
                    <span class="now">￥{{food.price}}</span>
                    <span class="old" v-if="food.oldPrice">￥{{food.oldPrice}}</span>
                  </div>
                  <div class="cartcontrol-wrapper">
                 <CartControl :food="food"/>
                  </div>
                </div>
              </li>
            </ul>
          </li>
        </ul>
      </div>
      <ShopCart />
    </div>
    <Food :food="food" ref="food"/>
  </div>
</template>


<script>
//第一步安装better-scroll组件  cnpm i better-scroll --save-dev
//第二步引入better-scroll
  import BScroll from 'better-scroll'
  import {mapState,mapActions} from 'vuex'
  import CartControl from '../../../components/CartControl/CartControl.vue'
  import Food from '../../../components/Food/Food.vue'
  import ShopCart from '../../../components/ShopCart/ShopCart.vue'
    export default {
    data() {
      return {
        scrollY: 0, // 右侧滑动的Y轴坐标 (滑动过程时实时变化)
        tops: [], // 所有右侧分类li的top组成的数组  (列表第一次显示后就不再变化)
        food: {}, // 需要显示的food
      }
    },
    components:{
      Food,
      CartControl,
      ShopCart
    },
    computed:{
      ...mapState(['goods']),

      currentIndex(){
        let {tops,scrollY}=this;
        let Index=tops.findIndex((item,index)=>{
          return scrollY>=tops[index]&&scrollY<tops[index+1]
        })
        // console.log(Index)
        return Index;

      }
    },
    mounted(){
      this.getShopGoods(()=>{
        this.$nextTick(()=>{
          this._getScroll();
          this. _initTops();

        })
      })

    },
    methods:{
      ...mapActions(['getShopGoods']),
      _getScroll(){

        //配置菜单栏卷帘
        this.menu=new   BScroll('.menu-wrapper',{
          probeType:3,
          click:true
        });
          //配置商品栏卷帘
        this.foods=new BScroll('.foods-wrapper',{
          probeType:2,
          clikc:true
        });
        //点住屏幕滚动的位置跟踪
        this.foods.on('scroll',({x,y})=>{
            // console.log(x)
            // console.log(y)
        });
        //点住屏幕滚动后松开屏幕后的位置  不松屏幕没值
        this.foods.on('scrollEnd',({x,y})=>{

          console.log(y)
          //取绝对值
          this.scrollY=Math.abs(y)
        })

      },
      //创建  初始化tops值
      _initTops(){
        let tops=[];
        let top=0;
        //tops值归0
        tops.push(top);
        //<ul ref="foodsUl"></ul> dom元素里要有对应的ref值
        //获取虚拟DOM元素food的大li  是为伪数组
        let lis=this.$refs.foodsUl.children;
        // console.log(lis)
        Array.from(lis,(li,index)=>{
          //获取每个大li的高度 也就是每一分类下ul的高度
          let h=li.clientHeight;

          //每次点击top值都是卷上去li高度的叠加
          top+=h;
          tops.push(top);
        })
        console.log(lis);
         console.log(tops);
        this.tops=tops
      },
      //创建点击菜单商品栏跟随滚动效果
        clickMenuItem(myIndex){

          console.log(myIndex);
      //  scrollTo(x, y, time, easing); => 滚动到指定的位置
      // x: x轴位置，
      // y: y轴位置
      // time: 滚动动画时长
      // easing: 缓动函数 不建议修改
      //此时的index值已经等于每个菜单下面所含得的商品li数
      let topHeight=this.tops[myIndex];
      this.foods.scrollTo(0,-topHeight,300)
        },
              // 父组件向子组件传递数据 展示不同的内容
        //showFood
    showFood(Food) {

          this.food=Food;
          this.$refs.food.toggleShow()


        }
    },


  }


</script>

<style lang="stylus" rel="stylesheet/stylus">
  @import "../../../common/stylus/mixins.styl"
  .goods
    display: flex
    position: absolute
    top: 195px
    bottom: 46px
    width: 100%
    background: #fff;
    overflow: hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px
      background: #f3f5f7
      .menu-item
        display: table
        height: 54px
        width: 56px
        padding: 0 12px
        line-height: 14px
        &.current
          position: relative
          z-index: 10
          margin-top: -1px
          background: #fff
          color: $green
          font-weight: 700
          .text
            border-none()
        .icon
          display: inline-block
          vertical-align: top
          width: 12px
          height: 12px
          margin-right: 2px
          background-size: 12px 12px
          background-repeat: no-repeat
        .text
          display: table-cell
          width: 56px
          vertical-align: middle
          bottom-border-1px(rgba(7, 17, 27, 0.1))
          font-size: 12px
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        font-size: 12px
        color: rgb(147, 153, 159)
        background: #f3f5f7
      .food-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        bottom-border-1px(rgba(7, 17, 27, 0.1))
        &:last-child
          border-none()
          margin-bottom: 0
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          .name
            margin: 2px 0 8px 0
            height: 14px
            line-height: 14px
            font-size: 14px
            color: rgb(7, 17, 27)
          .desc, .extra
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
          .desc
            line-height: 12px
            margin-bottom: 8px
          .extra
            .count
              margin-right: 12px
          .price
            font-weight: 700
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240, 20, 20)
            .old
              text-decoration: line-through
              font-size: 10px
              color: rgb(147, 153, 159)
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: 12px
</style>
